She won't forget, but she definitely won't be expecting it right away, because she doesn't expect him to already have the supplies ready, namely a ring. She doesn't really need a proposal, she knows they're it, end of the line, but

I could be nice.

She laughs at her precious family's antics, grinning as Mateo leaps from the water and showers them all in a fine spray of water droplets, making his sister shriek in delight, whole little body jerking and jumping in wonder. Object permanence is a hell of a thing.

"You found me! Mama, Luna found me."

Jyn laughs softly. "I can see that, she's a very good detective, you two will have to be partners."